We are using computer simulation methods (Monte Carlo and molecular dynamics) to study the properties of water and aqueous solutions of non-polar solutes, polar solutes, and ions. We are investigating ways of making these methods more efficient and have found that truncation of the water-water intermolecular potential at a distance of 6 Angstroms leads to a significant improvement in speed with no significant effect on the calculated short ranged structure. We are writing code for a Floating Point Systems AP120B Array Processor to do simulation calculations.